1. Field of the Invention
The present invention relates to a work vehicle coordinating system configured to carry out a ground work by a main work vehicle and an un-manned controlled sub work vehicle that follows up the main work vehicle.
2. Description of the Related Art
From U.S. Pat. No. 6,052,647, there is known a vehicle control system configured to determine target traveling positions one after another based on actual traveling positions of a main work vehicle and to control a sub work vehicle toward the respective target traveling positions. In this vehicle control system, there are disclosed e.g. a control mode causing the sub work vehicle to follow the main work vehicle in such a manner to maintain offset amounts along the X (longitude) direction and the Y (latitude) direction set for the main work vehicle and a further control mode causing the sub work vehicle to follow up the main work vehicle along a target traveling path which is a traveling path obtained by translating a traveling path of the main work vehicle by a working width amount thereof. In this, the traveling positions of work vehicle are obtained with using a GPS (Global Positioning Satellite System). An un-manned or radio-control technique of a tractor based on traveling position information acquired by GPS is described in details in U.S. Pat. No. 6,052,647.
A follow-up control disclosed in U.S. Pat. No. 6,732,024 is designed for a work in a huge work ground, not for a work in a work ground having a relatively small area demarked by a ridge or the like, such as agricultural field. In a typical cutting/harvesting operation effected in such agricultural field, firstly, a circumference work is carried out along the boundary such as a ridge or the like. In succession, before and after a turn (180-degree direction turn) using the worked area created by the circumference work as a turning area, a forward path traveling and a reverse path traveling are effected in repetition, thus completing a ground work in a reliable and gapless manner. Further, in e.g. a rice planting operation, firstly, the circumference area along the boundary such as a ridge is left un-worked and a work on this circumference area is carried out last. In any case, in an actual work, forward and reverse work traveling and the turn traveling therebetween will be repeated. However, with the follow-up mode disclosed in e.g. U.S. Pat. No. 6,732,024 not taking turn traveling into consideration, follow-up of the turn traveling becomes difficult.